I vote for a 10/22 carbine with a 10x50 fixed power scope and CCI Velocitor 40 gr hollow points. From a safe distance of 30 or 40 feet you could blast the head clean off the poor beast before it even knows you were shooting at it. But I would want my grandma backing me up with her 30-30 just in case that didn't stop it. They might have funny habits like those lizards that drop their tail and it wiggles and his around like crazy while he gets away. Grandma is older than me and she might know better which one to shoot. The headless dinosaur or the flip flopping tail.